On electric discharge machining, the worked surface receive the higher heating action in extremely short time, a part of electrode are vaporized, the other are melted, but it is difficult to be removed the whole of the molten part by discharge pressure. Any molten part remain as melting remnant zone under which heat affected zone is formed, and educed carbide, material of the opposite electrode are sticked on the dischage crater. Those zone afford the influerce on the machining characteristics.
This paper shows mainly the measured result of melting remnant zone and heat affected zone on worked surface.
1) Those Zones gradually increase as the discharge energy is increased, and the discharge duration has special effects upon the product of zone, The above mentioned phenomena varries due to the working fluid and working electrode materials.
2) The thickness of the melting and heat affected zone resulting from the heat influence of repeating discharge is decreased, as compared with the single discharge.
3) The maximum quantity of melting remnant is about 70% of total molten material. For increasing the removal efficiency, it is necessary to produce effective discharge pressure, when the quantity of the molten material is great.
4) Shape of melting remnant may affect to repeating discharge stability.
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